O, o-dimethyl-s-(1, 2, 2-trichloroethyl) monothiophosphate



United States Patent This is a continuation-in-part of application Serial No. 366,609, filed May 11, 1964, which in turn is a division of application Serial No. 158,888, filed December 12, 1961, now Patent 3,184,337.

The present invention relates to a novel thiophosphate.-

An object of the present invention is to prepare a novel S-polychloroethyl thiophosphate.

An additional object is to develop an improved nematocide.

Another object is to develop an improved insecticide of low mammalian toxicity;-

A further object is to develop an improved bactericide."

Yet another object is to develop an improved fungicide.

Still further objects and the entire scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

It has now been found that these objects can be attained by preparing 0,0-dimethyl-S-(1,2,2-trichloroethyl) monothiophosphate having the formula This compound is more active than the isomeric 0,0- dimethyl-S-(2,2,2-trichloroethyl) monothiophosphate as a nematocide. It was also effective as a bactericide The temperature of reaction can be varied, e.g., room temperature can be employed. However, preferably the reaction is initiated at lower temperatures since the sulfenyl halides have a tendencyto decompose at elevated temperatures.

The general procedure for preparing 0,0-dimethyl-S (1,2,2-trichloroethyl) monothiophosphate was as follows:

A known quantity of dimethyl phosphite was dissolved in 2-3 parts of dry carbon tetrachloride as a solvent and cooled to '0" C. by means of an ice bath. The apparatus was protected from-atmospheric moisture and connected to a 200-250 mm. Hg vacuum, which was applied throughout the total reaction period to assist in removal of the HCl formed. Slightly less than an equimolar quantity of the desired sulfenyl chloride was then added dropwise to the well stirred dimethyl phosphite-carbon tetrachloride solution. The addition rate was adjusted to maintain the reaction temperature between 4 and 8 C. For 0.1 molar quantities, 30 to 40 minute periods were necessary for this operation. The reaction rate was very high and easily visible by the almost instantaneous decoloration of the reacting sulfenyl chloride which is of distinct orange to dark red colors.

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Toward the end of the sulfenyl chloride addition, however, the reaction slowed down considerably. The reaction mixture was allowed to warm to room temperature and stirred for 1-1.5 hours at that temperature to complete the reaction. In many cases the products were left overnight at room temperature before the isolation of the desired reaction product was undertaken.

The vacuum was then disconnected, the mixture cooled to 05 C. and water was added slowly with stirring at a temperature not over 15C The product 9.0 grams (0.082 mol) of dimethyl; phosphite were dissolved in 20 ml. of dry carbon tetrachloride andtreated in the manner described above with 15 grams (0.075

mol) of 1,2,2-trichloroethyl sulfenyl chloride to give 17.5 grams yield) of practically pure.0,0-dimethyl-S-(1,2,2-trichloroethyl) thiophosphate as a dark yellow oil, n 1.5112. Distillation proceeded without decomposition at 113-114 C. at 0.06 mm. Hg to give the pure product as a yellow oil, 11 1.5120, .d 1.5254, Cl 39.3% (theory 38.9%), S 11.5% (theory 11.7%), P 11.4% (theory 11.3%). The infrared spectrum showed absorptions at 1275 cm.- (P=0), 1010-1070 cm? (P--OC) and at 725 and 750-810 cm.- The C=C peak at about 1560 cm.- was missing. c

The compound of the present inventionvcan be used alone as a nematocide, fungicide, bactericide or insecticide but it has been found desirable to apply it'to'the pest, e.g., to the soil habitat of nematodes, together'with 'inent solids to form dusts, or more preferabl'y'suspen-ded in a suitable liquid diluent, preferably water. There can also be added surface'active agents and inert solids in such liquid formulations. Desirably, 0.054% by weight of surface active agent is employed. The active ingredient can be from 0.01 to by weight of the entire composition in such cases.

In place of water there can be employed organic solvents as carriers, e.g., hydrocarbons such as benzene, toluene, xylene, kerosene, diesel oil, fuel' oil, and petroleum naphtha, ketones such as acetone, methyl ethyl ketone and cyclohexanone, chlorinated hydrocarbons such as carbon tetrachloride, chloroform, trichloroethylene and perchloroethylene, esters such as ethyl acetate, amyl acetate and butyl acetate, ethers, e.g., ethylene glycol monomethyl ether and diethylene glycol monomethyl 'ether, alcohols, e.g., ethanol, isopropanol and amyl alcohol, etc.

The novel pesticide can also be applied as an aerosol, e.g. by dispersing it in air by means of a compressed gas such as dichlorodifiuoromethane or 'trichlorofluoro- I methane and other Freons.

The pesticide of the present invention can also be applied with inert nematocidal, fungicidal, bactericidal or insecticidal adjuvants or carriers such as talc, pyrophyllite, synthetic fine silica, Attaclay, kieselguhr, chalk, diatomaceous earth, lime, calcium carbonate, bentonite, fullers earth, cotton-seed hulls, wheat flour, soyabean flour, pumice, tripoli, wood flour, walnut shell flour, redwood flour and lignin.

It is frequently desirable to incorporate a surface active cidal activity the thiophos'phates were formulated as wetta'ble powders consisting of 50% thiophosphate, 46% Hi-Sil 233 (ultra :fine silica), 2% Marasperse N (sodium lignin sulfonate) and 2% Pluronic L-61 (polyethylene agent in the pesticidal compositions of this invention. 5 oxide-propylene oxide molecular weight about 1000). Such surface active agents, i.e., wetting agent, are advan- This wettable powder is hereinafter designated as Form-utageously employed in both the solid and liquid composilation A. tions. The surface active agent can be anionic, cationic These 50% by weight thiophosphate containing wetor nonionic in character. table powders were diluted with water to such an extent Typical classes of surface active agents include alkyl 1 as to obtain final concentrations of the thiophosphates sulfon-ate salts, alkylaryl sulfonate' salts, alkyl sulfate of 200, 100, 50, 25 and 12.5 p.p.m. during the actual salts, alkylamide sulfonate salts, alkylaryl polyether altests. cohols, fatty acid esters of polyhydric alcohols and the The saprophytic nematode tests were carried out in alkylene oxide addition products of such esters, and addiwater as the medium with Panagrellus and Rhabditis spp. tion products of long chain mercaptans and alkylene oxat room temperature. The results were recorded as perides. Typical examples of such surface active agents incent kill after a 4 days incubation period. In Table 1 clude the sodium alkyl benzene sulfonates having 14 to there was used pure trichloroethyl thiophosphates. In 18 carbon atoms in the alkyl group, alkylphenol-ethylene a blank run the mortality was 5%.

Table 1 Compound 200 100 50 12.5

p.p.m. p.p.m. p.p.m. p.p.m. p.p.m.

(MeO)gP(O)SCHClCHCl1 100 100 so so so (EtO)zP(O)SCHClCHClz 100 100 100 100 so (2-EtHexO) P(0)SCHGICHCIQ- 20 5 5 5 5 (MeO)2P(O)SOHzCCl3 100 60 5 5 oxide condensation products, e.g., p-isooctylphenol con- 0,0 dimethyl-S-(1,2,2 trichloroethyl) monothiophosdensed with 10 ethylene oxide units, soaps, e.g., sodium 30 phate was tested as a bactericide. It was incorporated in stearate and potassium oleate, sodium salt of propylnaph- Formulation A and this mixture added to an agar culture thalene sul-fonic acid, (di-2-ethyl hexyl) ester of sodium of the bacteria. At 1000 p.p.m. it showed activity against sulfosuccinic acid, sodium lauryl sulfate, sodium salt of Erwinia carotovora and Xanthomonas vesicatoria and it the sulfonated monoglyceride of coconut fatty acids, was effective against Pseudomonas coronafacions at a consonbitan sesquioleate, lauryl trimethyl ammonium chlocentration as low as 100 p.p.m. ride, octade'cyl trimethyl ammonium chloride, polyethyl- 0,0 dimethyl-S-(1,2,2-trichloroethyl) monothiophosene glycol lauryl ether, polyethylene esters of fatty acids phate was also tested as a fungicide in a plate fungicide and rosin acids, e.g., Ethofat 7 and 13, sodium 'N- test. It was made up into Formulation A and then added methyl N-oleyltaurate, Turkey red oil, sodium di butyl- 4o to agar cultures of the fungi. Against Pythium spp., it naphthalene sulfonate, sodium lignin sulfonate (Marasv was 100% effective at 1000 p.p.m. and 60% effectiveat perse N), polyethylene glycol stearate, sodium dodecyl- 100 p.p.m. Against Rhizoctonia it was 60% effective at benzene sulfonate, tertiary dodecyl polyethylene glycol 1000 p.p.m. and 10% effective at 100 p.p.m. thioether (Nonionic 218), long chain, ethylene oxide In tests against the Mexican bean beetles an aqueous propylene oxide-condensation products, e.g., Pluronic 61, dispersion was sprayed on the plants and it was found sonbitan monolaurate, polyethylene glycol ester of tall to be effective. Alternatively it could be sprayed on the oil acids, sodium octylphenoxyethoxyethyl sulfate, tris [ground surrounding the plants. (polyoxyethylene) sonbitan monostearate (Tween In Table 2 there is shown the percent control at two sodium dihexyl sulfosuccinate. hours at the indicated parts per million of several chemi- The solid and liquid formulations can be prepared by cals against the indicated insects. Table 2 Flourbeetle Hipuse German cockroacli' Compound 18 0 1,000 100 p.p.m 1,000 100 p.p.m. p.p.m. p.p.m. p.p.m.

(MeOhi 0 CHClOHCh 100 100 100 100 100 ll (MeOhPSCHClCHOh 100 100 100 ll (MeOhPSCHOl; 100 100 0 100 0 Emmi 0 OHOIOHOI, 100 100 100 100 100 (EtOMi SOHOICHCHQ 100' 100 100 100 100 any of the conventional methods. Thus the active ingredi- In mammalian toxicity studies, however, the 0,0-dient can be mixed with the solid carrier in finely divided methyl S (1,2,2 trichloroethyl) monothiophosphate form in amounts small enough to preserve the free-flowing proved to be considerably safer to use than the other property of the final dust composition. compounds as shown in Table 3 in which the rates of ap- In the following examples or tables illustrating nemato- 75 plication are set forth in m-g./k g. of rat body weight.

Table 3 Compound No. dead of 3 rats oral (10 mgJkg.)

neom oonoionon o (MeO) SCHClOHOl (MeOMI SCHCh (EtOhI OCHCIOHCh 0 II (Et0)zPSCHClCHCl2 It is of course important that any pesticide have low mammalian toxicity. Consequently the 0,0-dimethyl -S- (1,2,2-trichloroethyl) monothiophasphate can be employed for this reason as a pesticide in many areas Where the other compounds cannot.

The 0,0 dimethyl S dichloromethyl phosphate of Tables 2 and 3 is the compound of Birum Patent 2,931,- 753, Example 3. The 0,0-dimethyl-O-(1,2,2-trichloroethyl) phosphate and the 0,0-diethyl-O-(1,2,2 trich1oroethyl) phosphate of Tables 2 and 3 are typical examples of compounds coming within Whetstone Patent 3,027,296, the latter compound being made in Whetstone Example 3.

It is also of interest to note that the 0,0-dimethyl-S- 1;2,2-trichloroethyl) monothiophos'phate of the present invention has a much lower mammalian toxicity than its 0,0-ethyl homologue.

We claim:

0,0 dimethyl-S-(1,2,2-trichloroethyl) monothiophosphate.

No references cited.

CHARLES E. PARKER, Primary Examiner. 

